How to Connect Two RV Batteries

The batteries in your RV can be linked together using battery cables to boost the power of the batteries. The method of connecting the batteries determines how the extra battery will affect the original battery, as an extra battery can be used either to extend the life of the original, with a parallel connection, or to increase the power of the original, with a series connection. It is important that you choose the right method of connection to meet your needs.

Things You'll Need

• Two RV batteries
• Battery cables

Instructions

Series Connection

1. Connect the outgoing negative line to the negative port on the first battery.

2. Connect the positive port of the first battery to the negative port of the second battery, using a cable.

3. Connect the positive port of the second battery to the outgoing positive line.

Parallel Connection

1. Connect the outgoing negative line to the negative port of the first battery.

2. Connect the outgoing positive line to the positive port of the second battery. Each battery should now be connected to your RV at one port and left unconnected at the other.

3. Connect the first battery to the second battery with a cable running from the negative port of the first battery to the negative port of the second battery.

4. Connect the positive port of the first battery to the positive port of the second battery.

Tips & Warnings

• Do not operate on the batteries while the RV is running, and do not attempt to start the RV while anyone is touching the cables that are attached to the RV's batteries.

References

• RV Basics: RV Batteries Wiring Diagrams